Women who dye their hair can increase the risks of developing breast cancer by nearly 25 per cent, a study suggests.

These have become increasingly popular as an alternative to the traditional coil, which uses copper to prevent pregnancy, because they reduce the discomfort of periods.

Researcher Sanna Heikkinen, of the University of Helsinki and Finnish Cancer Registry, said: “There was a 23% observed increase in the risk of breast cancer among women who dyed their hair compared to those who didn’t.”

But she added that further research was needed to confirm the roles of hormonal contraceptives – specifically hormonal intrauterine device – and hair dyes in breast cancer.